Makes a validator tolerant of absent values.
Accepts undefined unconditionally, delegating anything else to the wrapped validator, so an optional property is constrained only when actually present.
undefined
The type of the present value
The validator applied to present values, omitted or disabled to accept any value
A validator reporting the violations a present value incurs
Makes a validator tolerant of absent values.
Accepts
undefinedunconditionally, delegating anything else to the wrapped validator, so an optional property is constrained only when actually present.